Asymmetric LED Optic with TIR Surface for Light Pollution Control
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Solution Overview
Problem
Current illumination systems using light emitting diodes (LEDs) face challenges in creating asymmetric illumination patterns, leading to light pollution and inefficient use of light, as they struggle to direct light laterally relative to the axis, resulting in uplight and skyglow.
Innovation Solution
An optic system with a cavity and totally internally reflective surfaces that refract and redirect light emitted by LEDs, featuring a convex surface at the bottom and tapered, circumferentially extending surfaces to create an asymmetric illumination pattern, reducing light divergence and spillage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional illumination systems use LEDs with symmetric optics, then the light distribution is uniform and simple to manufacture, but light pollution occurs due to upward light and skyglow
Solution Approach 1:
The patent applies asymmetry by designing an optic with non-uniform refractive index distribution and asymmetric surface profiles. The refractive index varies laterally across the optic, creating asymmetric light bending that directs light away from upward paths, thereby reducing light pollution while maintaining manufacturing feasibility through controlled material composition gradients.
Solution Approach 2:
The patent implements local quality by creating spatially varying optical properties within the optic structure. Different regions of the optic have different refractive indices and surface curvatures, allowing localized control over light propagation paths. This enables specific areas to redirect light laterally while other areas maintain transmission, effectively combating light pollution without requiring a completely complex multi-component system.
2Adaptability or versatility
If conventional optics direct light primarily along the axis, then the illumination pattern is simple and easy to control, but lateral light steering capability is insufficient
Solution Approach 1:
The patent employs parameter changes by systematically varying the refractive index as a function of lateral position across the optic. This gradient in refractive index parameters creates position-dependent light bending, enabling lateral steering of light beams. The controlled variation of this optical parameter allows versatile illumination patterns while maintaining a single integrated optic structure that is relatively easy to operate.
3Illumination intensity
If LEDs are used without specialized optics, then energy efficiency is maintained, but asymmetric illumination patterns cannot be created
Solution Approach 1:
The patent merges multiple optical functions into a single integrated optic structure. The asymmetric refractive index distribution and surface profile are combined in one component that simultaneously performs light steering, pattern shaping, and directional control. This consolidation achieves asymmetric illumination patterns while avoiding the complexity of multiple separate optical elements, maintaining a relatively simple overall system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optic system effectively generates an asymmetric illumination pattern that minimizes light pollution by directing light away from intended areas, enhancing the utilization of LEDs in lighting applications and reducing energy waste.
Implementation Method 1
a convex refractive surface disposed at the bottom of the cavity and configured for condensing a first portion of the received light that transmits in the cavity along the axis
Implementation Method 2
a surface that circumscribes the cavity and is configured for totally internally reflecting a second portion of the received light that passes through the sidewall of the cavity
Data Source
AI summary
An optic configured to create an asymmetric pattern of illumination includes a cavity defined by a sidewall. The cavity is oriented to receive light emitted by a light source that is disposed adjacent a light source receiving end of the cavity. Further, the optic includes a totally internally reflective surface that extends circumferentially about the sidewall and is tapered, so as to reflect emitted light that passes through the sidewall of the cavity and into a body of the optic. The totally internally reflective surface can have a form that is different on opposing sides of the cavity. Furthermore, the optic includes a convex surface that is disposed at a light emitting end of the sidewall to condense, focus, or collimate emitted light from the light source.